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Rob wrote:
....
If there is a remaining question, its how to test
for radiated efficiency.....
OK, how to. Keep in mind that we can generally treat receiving and transmitting as equal. So the easy way to do testing is to pick a local constant radiating source, a VOR for instance, a receiver where we can readout received signal strength and a calibrated attenuator.
1) Now we mock up the different forms of antenna to test and move to our antenna range (your local airport.) Place the antenna in the open on something like a camera tripod where you can move it up and down, connect to the attenuator, then the attenuator to the receiver. Set the attenuator for a nominal attenuation, say 10 dB. Tune to the VOR and take a signal strength measurement. Adjust the antenna up and down for maximum (this is because you are accounting for the energy bouncing off the ground.) Note the signal measurement.
2) Change antennas and repeat, but this time after maximizing, adjust the attenuator until the signal strength measurement matches that from 1). Note the attenuator reading.
3) Repeat 2) for each additional antenna variation.
4) Use the configuration that had the maximum attenuator rating.
Chas.
LNC2 360JM
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